basic stuff. Go to a local skate shop and they can usually help (please support a local shop instead of corporations and online shit). He won't need a pro deck nor top of the line trucks. A good basic set of Red's bearings should work for the wheels.
The key is to get him something that he will be able to learn tricks on or he will quit and waste the money you spent on it (but not go all out either in case he really doesn't like it). If you get the bargain basement Walmart shit, then he won't be able to really skate without tearing it to shit.
Here's a link for a range of what should work for him
http://shop.ccs.com/searchresults/N=...ome%3A%20Promo